Middle Earth's Fourth Age: An Alternate History

Not much is known or said about the state of Middle Earth in the Fourth Age, which begins when the most legendary figures of the War of the Ring (including Frodo, Gandalf, and Galadriel) leave Middle Earth for the Undying Lands.   So what happens afterwards? To a region diminished by war but hopeful for future prosperity? To elven lands when the most powerful of their number have fled?   In "present day," it has been hundreds of years since the War of the Ring. Humans, elves, dwarves, and hobbits continue an existence not entirely fraught with war but not entirely peaceful, either.   Elves -- not all of whom went to the West at the end of the Third Age -- trade and collaborate with humans, though they content to live in their own traditional pockets of the region in Ered Luin and the Trollshaws. Because of the lack of, continued developing technology to   Similarly, dwarves are rebuilding parts of Moria: the main difference this time is that they *really trying* not to dig too deep. They also realize they will have to become less isolated to compete in the emerging stable economy of Eriador, so part of rebuilding Moria includes a more stable trade route between Eriador and Rhovanion.   For humans, life is a bit less stable. The Reunited Kingdom of the early Fourth Age has disintegrated. Humans live in fractured states with general infighting along the borders, though Bree-town and its surrounding areas enjoy relative prosperity. With their varying tribes, the humans have more ethnic and cultural diversity, which gives them more problems...   Oh, and hobbits? Well, they are pretty much just chilling in the Shire, as hobbits do. They've developed some more efficient plows in the past few decades, I suppose.